Stable isotope geochemistry of the modern Shinfa River, northwestern Ethiopian lowlands: a potential model for interpreting ancient environments of the Middle Stone Age

2021 ◽  
pp. SP507-2020-219
Author(s):  
Neil J. Tabor ◽  
A. Hope Jahren ◽  
Lani Wyman ◽  
Mulugeta Feseha ◽  
Lawrence Todd ◽  
...  
Keyword(s):  
Oxygen Isotope ◽  
River Water ◽  
Carbon Isotope ◽  
Middle Stone Age ◽  
Dry Season ◽  
Wet Season ◽  
Oxygen Isotope Fractionation ◽  
Oxygen And Carbon Isotope ◽  
Calcareous Deposits ◽  
Stable Oxygen

AbstractSeveral years of weekly sampling of waters from the Shinfa River watershed in the lowlands of northwestern Ethiopia yielded 275 samples with δDvsmow and δ18Ovsmow values ranging from c. −10 to +100‰ and from c. −2 to +20‰, respectively. Wet season (summertime) Shinfa River water stable hydrogen and oxygen isotope values are among the lowest reported in this study, whereas the dry season (winter/spring) usually records a progressive trend towards +100 and +20‰, respectively. Overlapping with this interval of Shinfa River water sampling, air temperatures (n = 155) also were recorded at the same time; temperatures range from c. 18 to 47°C. The coolest temperatures occur during the summer wet season, associated with the arrival of the Kiremt rains in the region, whereas the warmest temperatures occur towards the end of the dry season. In order to evaluate the extent to which this rather extreme isotope hydrology is recorded in the sediments and biota of the Shinfa River system, both hardwater calcareous deposits precipitated on basalt cobbles by evaporation in the Shinfa River channel during the dry season and aragonite from three different modern bivalve mollusc species were collected and analysed for their stable oxygen and carbon isotope compositions. Hardwater calcareous deposit δ18Ovpdb and δ13Cvpdb values range from c. −2 to +5‰ and c. −9 to +7‰, respectively, and preserve a trend towards progressively more positive δ18Ovpdb and δ13Cvpdb values through the course of the dry season. Shinfa River mollusc aragonite powders (n = 51) were serially sampled from cf. Coelutura aegyptica, cf. Chambardia rubens and Etheria elliptica species. All species record oxygen and carbon isotopes between c. −2 and +7‰ and between c. −18 and −8‰, and each species records coherent trends between those extremes as well as a positive parametric correlation between measured oxygen and carbon isotope values. However, there does appear to be some variability of measured isotope values by species, suggesting that species-specific metabolic differences may impact the resulting range of aragonite stable carbon and oxygen values. Based upon the measured Shinfa River water δ18Ovsmow and corresponding water temperatures at the time of sampling, a possible range of Shinfa River calcite and aragonite δ18Ovpdb values were calculated in conjunction with well-established calcite–water and aragonite–water oxygen isotope fractionation equations. These ‘fictive’ calcite and aragonite δ18Ovpdb values range from c. −5 to +15‰, which is a much larger range than previously documented from analyses of the hardwater calcareous deposits and mollusc aragonite samples. The narrower range of values in the natural calcite and aragonite samples may be attributed to several mechanisms, including time averaging and environmental stress. Nevertheless, the stable oxygen isotopic compositions of these natural samples offer a minimum assessment of the environmental extremes which occur in this region today, and provide a model for reconstructing the environments of the past.

scholarly journals Paleoclimate and ecology of Cretaceous continental ecosystems of Japan inferred from the stable oxygen and carbon isotope compositions of vertebrate bioapatite

2021 ◽  
Vol 205 ◽  
pp. 104602
Author(s):  
Romain Amiot ◽  
Nao Kusuhashi ◽  
Haruo Saegusa ◽  
Masateru Shibata ◽  
Naoki Ikegami ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Oxygen And Carbon Isotope ◽  
Stable Oxygen

scholarly journals Stable Oxygen and Carbon Isotope Composition of Holocene Mytilidae from the Camarones Coast (Chubut, Argentina): Palaeoceanographic Implications

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3464
Author(s):  
Gabriella Boretto ◽  
Giovanni Zanchetta ◽  
Ilaria Consoloni ◽  
Ilaria Baneschi ◽  
Massimo Guidi ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Carbon Isotope ◽  
Isotope Composition ◽  
Temperature Shift ◽  
Carbon Isotope Composition ◽  
Isotopic Shift ◽  
Stable Isotope Composition ◽  
Oxygen And Carbon Isotope ◽  
Stable Oxygen ◽  
Southern Westerlies

The stable isotope composition of living and of Holocene Mytilidae shells was measured in the area of Camarones (Chubut, Argentina). The most striking results were the high δ18O values measured in samples older than ca. 6.1 cal ka BP. In the younger samples, the δ18O values remained substantially stable and similar to those of living specimens. Analysis of the data revealed the possibility for this isotopic shift to be driven mainly by changes in temperature probably accompanied by minor changes in salinity, suggesting cooler seawater before 6.1 cal ka BP, with a maximum possible temperature shift of ca. 5 °C. A possible explanation of this change can be related to a northward position of the confluence zone of the Falkland and Brazilian currents. This is consistent with the data obtained in marine cores, which indicate a northerly position of the confluence in the first half of the Holocene. Our data are also in line with the changes in wind strength and position of the Southern Westerlies Wind, as reconstructed in terrestrial proxies from the Southernmost Patagonia region.

scholarly journals Mountain adaptation of caprine herding in the eastern Pyrenees during the Bronze Age: A stable oxygen and carbon isotope analysis of teeth

2018 ◽  
Vol 484 ◽  
pp. 60-74 ◽  
Author(s):  
Juliette Knockaert ◽  
Marie Balasse ◽  
Christine Rendu ◽  
Albane Burens ◽  
Pierre Campmajo ◽  
...  
Keyword(s):  
Bronze Age ◽  
Carbon Isotope ◽  
Isotope Analysis ◽  
Oxygen And Carbon Isotope ◽  
Eastern Pyrenees ◽  
Stable Oxygen ◽  
Carbon Isotope Analysis ◽  
The Bronze Age

Paleomagnetic and geochemical evidence for a pre-Triassic age for the Lower Amaranth Member of the Williston Basin of Manitoba (Canada)

2009 ◽  
Vol 46 (11) ◽  
pp. 855-873 ◽  
Author(s):  
Erika Szabó ◽  
Maria T. Cioppa ◽  
Ihsan S. Al-Aasm
Keyword(s):  
Fluid Flow ◽  
Oxygen Isotope ◽  
Carbon Isotope ◽  
Carbon Isotopes ◽  
Geochemical Data ◽  
Williston Basin ◽  
Oxygen And Carbon Isotopes ◽  
Oxygen And Carbon Isotope ◽  
The Matrix ◽  
Expected Values

Paleomagnetic and geochemical data obtained from six wells in southwestern Manitoba indicate that the Lower Amaranth redbeds were deposited earlier than Jurassic or Triassic, the most commonly cited depositional ages for this formation in the Williston Basin. The magnetization is carried primarily by detrital specular and pigmentary hematite and occasionally magnetite. Inclination-only analysis of paleomagnetic data (83 specimens from 60 plugs) indicates two possible depositional magnetization ages: Devonian–Pennsylvanian (D, found in very few samples) or Carboniferous to Permian, as suggested by the inclination and the polarity of the most predominant magnetization (B). An isolated magnetization (C) could be a mid-Jurassic to Neogene localized fluid flow remagnetization event. The oxygen and carbon isotope values of dolomite (–6.45‰ to 0.30‰ Vienna PeeDee Belemnite (VPDB) δ18O, –1.57‰ to 5.44‰ VPDB δ13C; n = 18) indicate that dolomitization could have occurred anytime between Carboniferous and Jurassic. However, the distribution of these values is a function of the three types of dolomite present in the Lower Amaranth strata: detrital, cement, and matrix replacive and reflects both the primary values and diagenetic overprints. Detrital and cement dolomite show depleted values in both oxygen and carbon isotopes, most likely inherited from the original values of the detrital dolomite, with superimposed effects of recrystallization. The matrix replacive dolomite has no detrital content, and its oxygen isotope values are similar to the expected values for primary or early diagenetic dolomite from Carboniferous to Jurassic times. Mixtures of detrital and replacive matrix dolomite give intermediate oxygen and carbon isotope values.

scholarly journals Assessment of Surface Water Quality using Indices and Geographic Information System in the Sebou River Basin, Morocco

2021 ◽  
Vol 17 (10) ◽  
Author(s):  
Kanga Idé Soumaila ◽  
Naimi Mustapha ◽  
Chikhaoui Mohamed
Keyword(s):  
Water Quality ◽  
River Water ◽  
Oxygen Demand ◽  
Water Quality Monitoring ◽  
Dry Season ◽  
River Water Quality ◽  
Wet Season ◽  
Water Quality Variation ◽  
Quality Variation ◽  
Monitoring Stations

The aim of this study is to access the quality of monitored rivers and to map the polluted river sections in the Sebou basin using Geographic Information System (GIS). The potential causes of water quality variation will also be added for suitable measures to be taken. A Water Quality Index (WQI) which developed in Morocco was applied to 17 river water quality monitoring stations with data on 6 parameters (Dissolved oxygen (DO), ammonium ion (NH4 + ), 5-day biochemical oxygen demand (BOD5), chemical oxygen demand (COD), fecal coliforms (FC) and total phosphorus (TP)) collected twice during the wet and dry season over 1990-2017 period. The result shows that river water quality is classified as bad, very bad and medium at 59% of the monitoring stations, while 41% are considered as good to excellent. Interpolation of mean values of overall WQI of the 17 river water quality monitoring stations, revealed evidence of quality degradation along several kilometers of most river sections in the Sebou basin. The correlation matrix between the sub-indices of water quality parameters and the overall WQI showed high positive correlation coefficients and highlights the contribution to water quality degradation as follows: TP (𝑟 = +0.96 ) ≥ NH4 + (𝑟 = +0.96 ) > BOD5 (𝑟 = +0.94) > COD (𝑟 = +0.86) > FC (𝑟 = +0.83) > DO (𝑟 = +0.79). The sections of Fès, Innaounene Rivers, and an extended stretch of Tizguit River must no longer be used for irrigation. River water quality is overall of better quality in the wet season compared to the dry season. Simple linear regressions between the seasonal water quality variation and the overall WQI showed higher coefficients of determination R 2 (0.67 and 0.60) between dry season WQI and the overall WQI and between wet season WQI and the overall WQI respectively. It is clear that discharges of industrial and domestic wastewater during the dry season and agricultural activities are most likely to be the causes of the degradation of river water quality.

scholarly journals Seasonal variation in quality of Louhajong river water, Tangail

2016 ◽  
Vol 28 (1) ◽  
pp. 9-16
Author(s):  
Md Rakib Hasan Sarker ◽  
Asadul Islam ◽  
Ariful Islam ◽  
Md Mahbubul Hoque ◽  
Shimul Roy
Keyword(s):  
Seasonal Variation ◽  
River Water ◽  
Water Samples ◽  
Dry Season ◽  
Fish Culture ◽  
Chemical Parameters ◽  
Wet Season ◽  
Physico Chemical ◽  
Standard Level

Water samples were collected from three points of Louhajong river (Dighulia, Kagmari Bridge and Oloa) to see the seasonal variation in physico-chemical parameters. The results revealed that some of the parameters such as TDS, alkalinity and acidity have exceeded the standard level in dry season in all of the points, which are unsuitable for different purposes including fish culture. During dry and wet seasons the highest concentrations of BOD was recorded as 2.0 and 0.8 ppm at Kagmari Bridge (point-2) respectively. DO ranged from 1.4 to 3.1 and 2.4 to 3.8 ppm during dry and wet seasons. Maximum and minimum EC was recorded as 890 and 130 ?s/cm at Dighulia (point-1) during dry and wet seasons. The results suggest that at wet season Louhajong river may be suitable for fish culture and other purposes.Bangladesh J. Sci. Res. 28(1): 9-16, June-2015

scholarly journals Occurrence ofBlastocystissp. in water catchments at Malay villages and Aboriginal settlement during wet and dry seasons in Peninsular Malaysia

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2541 ◽  
Author(s):  
Samseh Abdullah Noradilah ◽  
Ii Li Lee ◽  
Tengku Shahrul Anuar ◽  
Fatmah Md Salleh ◽  
Siti Nor Azreen Abdul Manap ◽  
...  
Keyword(s):  
River Water ◽  
Water Samples ◽  
Water Sources ◽  
Dry Season ◽  
Parasitic Infections ◽  
Wet Season ◽  
River Water Samples ◽  
Sampling Points ◽  
Dry Seasons ◽  
Wet And Dry Seasons

In the tropics, there are too few studies on isolation ofBlastocystissp. subtypes from water sources; in addition, there is also an absence of reported studies on the occurrence ofBlastocystissp. subtypes in water during different seasons. Therefore, this study was aimed to determine the occurrence ofBlastocystissp. subtypes in river water and other water sources that drained aboriginal vicinity of highly endemic intestinal parasitic infections during wet and dry seasons. Water samples were collected from six sampling points of Sungai Krau (K1–K6) and a point at Sungai Lompat (K7) and other water sources around the aboriginal villages. The water samples were collected during both seasons, wet and dry seasons. Filtration of the water samples were carried out using a flatbed membrane filtration system. The extracted DNA from concentrated water sediment was subjected to single round polymerase chain reaction and positive PCR products were subjected to sequencing. All samples were also subjected to filtration and cultured on membrane lactose glucuronide agar for the detection of faecal coliforms. During wet season,Blastocystissp. ST1, ST2 and ST3 were detected in river water samples.Blastocystissp. ST3 occurrence was sustained in the river water samples during dry season. HoweverBlastocystissp. ST1 and ST2 were absent during dry season. Water samples collected from various water sources showed contaminations ofBlastocystissp. ST1, ST2, ST3 and ST4, during wet season andBlastocystissp. ST1, ST3, ST8 and ST10 during dry season. Water collected from all river sampling points during both seasons showed growth ofEscherichia coli and Enterobacter aerogenes, indicating faecal contamination. In this study,Blastocystissp. ST3 is suggested as the most robust and resistant subtype able to survive in any adverse environmental condition. Restriction and control of human and animal faecal contaminations to the river and other water sources shall prevent the transmission ofBlastocystissp. to humans and animals in this aboriginal community.

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